Cadmium is a rare metallic element found in small deposits on almost every continent. It has a number of uses, perhaps most famously as a pigment in paint, and it can be expensive due to its rarity. This element is also toxic, and it should be handled with care; people who are exposed to cadmium because of their occupations should exercise routine cautions, as it will bioaccumulate, concentrating in the body without being eliminated like other toxins are.
Pure cadmium is rare in nature. The element is usually found in combinations with other elements, typically copper, zinc, and lead. It is extracted from these ores during the smelting process, or with the assistance of chemicals such as sulfuric acid. When isolated, cadmium is a soft, bluish white metal that is highly ductile, making it extremely suitable for metal alloys. The element's atomic number is 48, and it is identified on the periodic table of elements with the symbol Cd, among the transition metals.
Fredrich Stromeyer identified cadmium in 1817, when he was studying zinc and its impurities. The element is named for the Greek god Cadmus, who had an adventurous life around 2000 BCE, according to Greek mythology. Initially, the toxicity of cadmium was not recognized, and it was even used as a medical treatment until scientists realized how harmful the element was. This practice is actually surprisingly common with many chemical elements, such as lead and arsenic, both of which were used in makeup compounds historically.
Most of the world's cadmium is used in the production of batteries, particularly rechargeable batteries such as nickel-cadmium batteries. It's also used to create yellow, orange, and red pigments, and it is sometimes added to plastics as a stabilizer. The element is also used in alloys, solders, and some semiconductors, and there are numerous uses for its compounds as well as the element itself.
Cadmium and its compounds are generally considered to be carcinogenic by most health and safety agencies. The element irritates internal organs such as the lungs and intestines when inhaled or ingested, and long term exposure to high levels can cause death. People are exposed to metal through occupations that involve its use, along with polluted air and water. Once cadmium has polluted an area, it can also be very difficult to remove; this is a major issue in areas where the metal is mined and processed.
By Mary McMahon
Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All The Science researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.